A dead platform is a dead platform is a dead platform.
Nice. I've never cared for what is considered
"dead" by whoever is the authority.
And offline machines are still at risk for local attacks from things like USB payloads that rely on older OS exploits.
How many of these attacks have you encountered yourself? How many managed to penetrate security of your main system in order to infect USB sticks you are about to connect elsewhere? Wait… if that happened, the still supported, secure
"not dead" system got infected. Of course the air gap can be bridged to infect and damage isolated systems (Stuxnet). The question is how likely it is that this is going to happen by playing a few games offline.
Furthermore: Why should I care for malware attack on an offline PC? What will it do?
Grab banking credentials? Mine Bitcoin? Try to dox me? Run a keylogger to sniff passwords? Delete data or demand ransom for a mostly empty computer with the backup image lying next to the system?
I even started malware on purpose just to see what it does.
This leaves targeted hardware destruction as threat (overwrite BIOS for example). I'll accept that risk for worthless old systems.
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Following that
"it's dead" logic I would be forced to scrap all of my old computers because they won't be able to run
any current (supported) software. There is nothing wrong with running old systems in isolated environment. Sadly Steam is
*THE* PC game platform for quite some time now. Numerous games and PCs considered old (and
"dead") themselves by the majority have already been sold in the
new-and-better-digital-only world. Most of these games are tied to the Steam background services (or whatever this should be called) and there is no reason to not continue playing them on outdated systems that can handle them.
I'm really shocked by the amount of RAM the Steam service needs for nothing – just assuming people obey to the never ending cycle of waste and simply buy the latest and greatest every two years never noticing the bloated design. As long as there is no technical reason a software should still run on outdated platforms. A game launcher would theoretically work on 30+ year old hardware.